A union has set up a food bank in the Whitehall office of a government department after a pay error meant some cleaners and support staff were left short.
The PCS union said some of its members set it up in response to pay problems.
A small number of staff employed by outsourcing contractor ISS are understood to have been affected.
ISS is meeting any “additional costs” staff incur, the Business, Energy and Industrial Strategy department said.
Danish support services company ISS took over the cleaning and other support services contract for the government department at the start of March.
ISS said it was “extremely sorry” for what it said were errors in the processing of some employees’ payroll since it took over the contract.
It told the BBC all the issues it was aware of had now been resolved.
The PCS union – the UK trade union for civil and public servants, and private sector workers on government contracts – said staff had experienced difficulties including being owed back pay and not being paid on time which meant some staff did not have the necessary funds to get to work.
The Sunday Times, which first reported the story, said union officials had asked for food donations at four drop-off points set up in the ministry.
But the Business, Energy and Industrial Strategy department (BEIS) said ISS had resolved the issue, including paying the money owed to the contractors.
BEIS added that they were “in daily contact with ISS, who are meeting any additional costs incurred by staff due to the error and are contacting every contractor to ensure any further errors not yet identified are resolved within the same day”.
It is not known exactly how many workers are affected but the PCS union put the figure at “dozens”.
General Secretary Mark Serwotka blamed “mismanagement of the contract” by ISS for the problem.
“This underlines why all contracted out services in BEIS and other government departments must be brought back in house as a matter of urgency,” he added.